Mono is capable of causing serious complications, but these usually are limited to individuals who have already been diagnosed with underlying medical conditions. The good news is that most cases of mono are mild and don't cause prolonged absences from school or work.

Main symptoms of mono
Not everyone infected with the virus that causes mono (Epstein-Barr virus, or EBV) manifests symptoms. This is especially true in young children, who may have a fever but no other symptoms. People between the ages of 10 and 24 are most likely to exhibit obvious symptoms. Signs and symptoms of mononucleosis may include:

• fatigue
• fever
• headache
• loss of appetite
• night sweats
• skin rash
• soft, swollen spleen
• sore throat, perhaps a strep throat that doesn't get better with antibiotics
• swollen lymph nodes in your neck and armpits
• swollen tonsils
• weakness

Complications
In a smaller percentage of people there may be complications such as jaundice (a yellowing of the skin due to liver damage), enlargement of the spleen, and even rarer complications such as encephalitis (brain inflammation). In half of those diagnosed with mononucleosis with symptoms, the spleen enlarges, and in about 20%, the liver also swells. The organs slowly return to normal after the infection; however, there's a small but real chance of the spleen rupturing.

• encephalitis
• enlargement of the spleen
• jaundice
• spleen rupture
• swelling of the liver

When to seek help
If rest and a healthy diet don't ease symptoms within a week or two or if symptoms recur, see a doctor. If you have been diagnosed with mono and have tried home treatment for 7 to 10 days, seek care from a doctor if you experience:

• a lack of energy
• body aches
• a severe sore throat that has lasted longer than 2 to 3 days
• swollen glands

If you have been diagnosed with mono seek medical care immediately if you experience:

• breathing problems
• severe pain in the upper left part of the abdomen (sign of a ruptured spleen)
• tonsils that are so swollen it is difficult to breathe or swallow.

As soon as a person gets over mono, symptoms will go away for good, but they will always carry the virus that caused it. The virus may become active from time to time without causing any symptoms. When the virus is active, it can be spread to others. But how do doctors diagnose the virus that causes mono? And what tests can you expect at the doctor's office? Continue reading for more information. We'll cover how to diagnose mono in the next section: Diagnosing Mononucleosis.